Tube-making machine



April 27 1926. o. VS :|-u Er\1sTEDT TUBE MAKING MACHINE Filed April 25, 1925 Figi.

Il II/////////////// l l Manley Patented Apr. 27, i926.

. entre erases,-

DRA'ULIK GESELLSCHAFT MIT BESCI-I MANY, A snai/miv COMPANY.

rUBE-MAKING MACHINE.

. YApplicationfined Api-.1 1 25, 1925. serial No. 25,863,

To all whom t may concern."

Beit known that I, Oswre SGHLENSTEDT, a citizen of the German Republic, residing at 64E Hundsbuschstrasse, Mulheim-Ruhr- Speldorf, Germany, havey invented certain new and useful Improvements Relating to Tube-Making Machines, of which the following is a specification. l

The. present invention relates to a press for making tubes of the type comprising a mandrel, die and ram. In suchpresses during the operation of pressing out the work the mandrel is subjected by the flowing metal to greatstresses which, in presses in which the mandrel `is'counected to the ram or to a hydraulic piston that especially servesmfor reciprocating the mandrel, often result 1n the fracturev of the latter. v

The invention especially relates to presses of the type referred toin which the mandrel is mounted so as to be .capable of freemovement under the influence of the. flowing metal duringthe operation of pressing out the work.

According to the invention they mandrel is mounted freely movable in the axial direction whereby the mandrel alone is'subject to the free'play of theextruded metal,that is, the mandrel is capable of moving with the extruded metal to an extent that is determined by the movement ofthe metal. within the holder, and a `head orthe like-is provided upon therear end ofV the mandrel so that it may be retracted on the withdrawal of the ram.

In the accompanying drawing,

Figure 1 is a -central section through a press illustrating the invention in oneA form.;

Fig. 2 is a` central section` through a ram showing an axially movable mandrel having a head fitting in a bore in the ram;

Fig. 3. is a central section throughl alpress in which a rod has a limited, axial movement in the pressing member, and a headed mandrel. has a lost-motion connection withV the rod; s

Fig. 4 is a similar view through another form of pressl embodying, a rod having, a limitedaxial movement in thepressing mem'- ber and a headed mandrel having Ya lostmotion connection' with theV rod g, v

F ig. `Sis a central section through part of a pressing member, showing a mandrel hav ing a head adapted to engage the rear end ofl head, has a limited axialimovement. in the.

pressing member and the mandrel is secured to said rod.

, i i terasse] Parser artefice.`

` In F iguresl to 6 of the accompanyingv drawings there are illustratedfa number of. constructions ,of a tube press provided withV a freelymovable mandrel. Inail-the figures, ci is the mandrel, b is the raw material tobe pressedv out, c is the. ram which presses out the raw material b, al is the holder for the raw material, and f is the die or matrix which provides an annular opening for the passage of the raw material being pressed by the ram c. g is a pressure disc, which is placed in the usual way in front of the end face of the ram c. 7i; is the pressure cylinder of the tube press, and 2' is the corresponding pressure piston which transmits the pressure applied, to the raw material. ZJ by means of they ram c. A return cylinder la is provided for withdrawing the pressure piston c' in known manner. The perforating cylinders l` with the corresponding pistons m, attached to the pressure piston 2', are used. for. moving the pressure piston 2' formed and for perforating vthe block bf i A simple formof mechanism is shown` in Fig. l in which a plain mandrel or punch is loosely insert-edinto a corresponding hole in the ram c, so that it can freely move in the direction in which pressure. is applied. The mechanism operates as follows: l

The block is passed into the holder al, whereupon water under pressure is admitted to the cylinders Z, whereby the pressure piston z' is movedy forward without load, together with the` ram c and the mandrel or punch. a, whereupon the 'block b is perforated. This operation causes the mandrel or, punch a to penetrate the die or matrix f andthe pressure disc g to come into contact with the perforated block` During this movement of the pressure piston z', the Vpressure cylinder /L is filled with water at low pressure. Thereupon the pressure cylinder 7L is placed under pressure, whereupon thevopervlos ation of prssingoutthe block Zi commences,

ln this operation the work exerts pressure upon t-he wall ot the holder (Z and upon the surface of the mandrel a, and such pressure results in trietion upon the mandrel as the work tends to move along the surface ot the mandrel, and to take the mandrel with it. The provision ot the mandrel d so as to move in the direction of its` axis allows the mandrel to yield to this eti'ort. ot the work unaffected by any external agency, and to take part in the. movement ot 'the work. In order that the mandrel may be uithdrawn from the tube produced, on the return movement ot the pressure piston, the mandrel a is provided at its rear end with a head n which may be integral er screwed on and which is guided in a corresponding bore of the tubular ram c. As the piston returns the mandrel is likewise drawn out by the forward end ot the ram, the bore et which corresponds to the diameter ot the mandrel, and it is thus withdrawn from the pressed tube. To prevent the tube from following the mandrel as the latter is being withdrawn a gripping device ot any dcsired construction, not illustrated in the drawings, may be provided at the rear ot the press. For this purpose the box oit the holder (Z may be somewhat larger near the die or matrix f, so that the remainder of the raw material within the holder (Z and which is still connected to the tube is held Vtast as the mandrel is being withdrawn.

' for advancing and returning the mandrel a.

A rod y passes centrally through the pref;- sure piston 'i which is reduced and extended at the rear, and the rod Q' is provided for transmitting the movement ot the advancin and returning piston p to the mandrel n. The mandrel a. is provided with a head n, and is inserted in the rod g in such manner that it can make the desired axial movement without being obligated to take the rod with it. The piston p is used on the one hand for perfor-ating the work block and on the other hand for withdrawing the mandrel from the pressed tube. For this purpose pressure is exerted tirst upon one side ot the piston and then upon the other side alternately. In the arrangement according to Figure 3. the pressure cylinder zi is set tor waste water only after the mandrel is withdrawn from the pres-;ed tube, tor the purpose ot' gripping the remainder of the work and the tube during the withdrawal ot' the mandrel by the ram c. The pistons m have for their only purpose in this construction to advancel the pressure piston until it comes into contact with the pressure dise g against the perforated work block.

The extension o of the pressure piston z' which is necessary tor allowing the axial movement ot the rod g may be provided with a piston s, which is packed in the reillustrated ifi evlinders r. 'the relative movement of the f cro:-1s-head with respect to the pressure pir#- ton e', that is to say the movement ot the cross-head in the slot u, has i'or its object to withdraw the. mandrel trom the presricd tube by the cylinders fr, and in doingl so to bald the tube firmly by the pressure pir-'ton 'i and the ram c, in the manner described with reference to i'1`igure il. rEhe c 'v'liuflers r may be used utter the witlulravval ot the mandrel Afrom the tube tor continuing` the movement of the cross-head at the same time as the returning cjvlindcrs are use-il tor he preesure piston e'.

The pressure piston may be provided to move without load by admitting vfat-e under low pressure into the pressure t inder 71. In this case the perliorating; inders only require to be put unde pres'- sure at the commencement of perit'oratien: or they may be dispensed with entirely it' the water pressure eirts a suiiiciently high pressure upon the pressure piston i to pertorate the block.

As is shown in Figure 5, the mandrel ,f may be made et such a length that the heart used for withdrawing the mandrel is limited in movement by the rear 'tace ot the ram e. rl`l1e disadvantage ot the greater length in this orm ot mandrel is counterbalanccd by the advantage ot a stronger ram c; the bore ot the ram reiuiirrs to be no more than equal to the diameter ot the mandrel.

As illustrated in Figure G the mandrel may be made divided in such manner that a plain mandrel is inserted in an extension fw provided with a head In, but this extension does not enter the pressed tube duringr the pressing operation.

Yfigure 7 illustrates a modification in which the lost motion or the capacity Vfor movement axially is not provided in the mandrel holder, but in the cylinder o ol the rod g. The return side ot the piston in the cylinder o is in this case connected with the waste water pipe when the tube is beingpressed out.

The tree movement ot thel mandrel a is somewhat ail'ected by the resistance of the water issuing ll'rom the cylinder o, and by the triction ot the piston`r but this arrangement has the afflvantage intended over the devices already in use although not to the extent attained in the other modilieations hereinbe'tore described.

The arrangement of mandrel illustrated Utl lei

lil?) in Figure 7 may be used in the construction shown in Figuret, With suitable obvious changes.

The modiiications ot construction hereinbetore described and illustratedin the accompanying drawing are intended merely as examples. l

It will be understood that the invention may be used on tube making presses ot other construction, provided the purpose intended by the invention is secured, that is, to allow the mandrel during the pressing operation to move forward merely by the effect of the Work uniniluenced by any out-- side agency.

By the use of apparatus according to the invention complete Work blocks can be pressed outl into tubes in a tube press, and before beginning the pressing operation the Work blocks can be perforated in the holder by the mandrel described, but the work blocks may be perforated and Worked up before introduction into the holder.

I claim l. A tube press ot the die and mandrel type comprising a pressing member composed of a piston and ram, a die, and a mandrel concentrically mounted in said member and having a lost-motion connection therewith permitting limited axial movement of the mandrel With respect to said member and preventing the separation of the mandrel from the ram when the latter is Withdrawn from the die.

2. A tube press of the die and mandrel type comprising a pressing member composed of a piston and ram, a die, and a mandrel concentrically mounted in said member and movable axially With respect thereto, said mandrel having a head at its inner end adapted to prevent the Withdrawal of the mandrel from the ram when the latter is Withdrawn from the die.

3. A tube press of the die and mandrel type comprising a pressing member composed of a piston and ram, a die, a rod, and a mandrel connected to the rod, said rod and mandrel being axially mounted in said member and having a lost-motion connection therewith, permitting limited axial movement of the rod and mandrel with respect to said member and preventing withdrawal ot the mandrel from the ram When the latter is Withdrawn from the die.

4. A tube press of the die and mandrel type comprising a pressing member composed of a piston and ram, a die, a rod, a mandrel connected to the rod, said rod and mandrel being' axially mounted in said member and having a lost-motion connection therewith, permitting limited axial movement ot the rod and mandrel with respect to said member and preventing Withdrawal of the mandrel from the ram When the latter is withdrawn from the die, and means for moving said rod independently ot' said member.

5. A tube press of the die and mandrel type comprising a pressing member com posed of a piston and ram, a die, a rod concentrically mounted in said member and having a lost-motion connection With said meniber permitting limited axial movement of the rod with respect thereto, and a mandrel movable axially in the ram and having a lostmotion connection with the rod.

6. A tube press of the die an-d mandrel type comprising a pressing member composed of a piston and ram, a die, a rod concentrically mounted in said member and movable axially With respect thereto and a mandrel movable axially in the ram and having a lost-motion connection With said rod.

7. A tube press of the die and mandrel type comprising a pressing member composed of a piston and ram, a die, a rod concentrically mounted in said member and movable axially with respect thereto and a mandrel movable axially in the ram andk movable relatively to the rod, said mandrel having a head adapted to prevent its Withdrawal from the rod and ram when the latter is Withdrawn from the die.

OSWIG SCHLENSTEDT. 

